The present invention relates to an apparatus and method for improving the extraction of flavor-containing materials such as coffee, tea, herb or cocoa with hot water or steam pulse and for improving the taste and quality of beverages.
It has been known for centuries to prepare coffee, tea, herb extracts and other flavor-containing liquids by steeping the corresponding flavor-containing solid materials in hot water under ambient or elevated pressure. The steeping of roasted and ground coffee under ambient pressure emerged in late 14th century and has been automated with the inventions of stove-top percolator in 1820""s, electric percolator in 1950""s, and automatic drip coffee maker in the 1970s. The steeping of ground coffee under elevated pressure, resulting in the well-known espresso drinks, emerged with the invention of steam espresso machine in 1910""s and later improved by the inventions of piston espresso machine in 1940""s and pump espresso machine in 1960""s.
Extraction time and temperature are among the most critical considerations when brewing coffee. Automatic drip coffee makers brew better coffee than percolators by avoiding re-boiling coffee and reducing extraction time, thus preserving the aroma and reducing coffee bitterness. (The bitter, less soluble chemicals in the grounds require longer extraction time.) Shorter extraction time, however, normally causes incomplete flavor extraction, which may have contributed to the weaker coffee made by most single-cup coffee makers and water displacement-type coffee makers (U.S. Pat. No. 5,200,221). It is generally believed that the best water temperature is between 197xc2x0 to 205xc2x0 F., which can be easily achieved by boiling water in a percolator but more difficult to achieve in automatic drip coffee maker.
In the applicant""s earlier U.S. Pat. No. 5,267,506, apparatus for making coffee, espresso, tea or the like by steeping the flavor-containing materials in hot water under elevated pressure are disclosed. In that patent, first and a second embodiments are described in which a cell in contact with a heating element draws an amount of water from a water reservoir and subsequently heats the water and generates pressurized steam above the hot water in the cell. In the first embodiment, the hot water in the cell is delivered to and through the flavor-containing materials under the pressure of the pressurized steam, and the pressurized steam is then released through an automatic steam release valve. In the second embodiment, the hot water under the pressure of the pressurized steam in the cell is first delivered and the pressurized steam is later delivered to and through the flavor-containing materials.
Such-apparatus have numerous advantages including higher brewing speed, less flavor loss and lower cost over known coffee makers and espresso machines described above. However, significant advancements can still be made with such apparatus to improve the taste and quality of the liquid extraction as well as the ease of use, safety and cost of the apparatus. In fact, the apparatus with the invention disclosed here were found to make surprisingly, drastically better tasting coffee than the best commercially available coffee makers when the same coffee grounds was used, according to expert tasting tests.
An apparatus for extracting flavor-containing materials such as coffee and the like is provided. The apparatus includes a water reservoir for receiving a supply of water, a container for containing an amount of the flavor-containing materials and for allowing the extraction of the flavor-containing materials under pressure therein, and a fluid deliver system. The fluid delivery system is provided for generating a plurality of pressure pulses, each pressure pulse including a hot water pulse and a steam pulse, and for delivering the plurality of pressure pulses through the flavor-containing materials in the container. This extracts the useful compounds out of the flavor-containing materials under the pressure of the pressure pulses. The fluid delivery system includes a chamber, a heater in heat conducting relation with the chamber to heat water in the chamber and to is produce steam. Also included is a conduit for delivering water from the reservoir to the chamber, and valve disposed in the conduit between the reservoir and the chamber which opens to permit water to flow from the reservoir to the chamber when pressure in the chamber drops below a predetermined pressure. Also included is a fluid passage connecting the chamber and the container to-allow the hot water and steam to be forced through the flavor-containing materials in the container by the pressure of the pressure pulse.
Another aspect of the invention is a method for making flavor-containing liquid by extracting flavor-containing material such as coffee or the like with a plurality of pressure pulses. The method includes generating and delivering a first pressure pulse in the form of a pressurized hot water pulse and a pulse of pressurized steam to and through the flavor-containing materials in a container. The flavor-containing materials are extracted by the pulse of pressurized hot water under the pressure of the first pressure pulse and are dried or potentially re-roasted by the pulse of pressurized hot steam. The next step is to generate and deliver a second pressure pulse comprising a pulse of pressurized hot water and a pulse of pressurized hot steam, again, to and through the flavor-containing materials in a container. Thus, the flavor-containing materials are extracted by the pulse of pressurized hot water under the pressure of the second pressure pulse and being dried or potentially re-roasted by the pulse of pressurized hot steam. The steps of generating and delivering pressure pulses to and through the flavor-containing materials are repeated until a desired amount of flavor-containing liquid has been prepared.
It is an object of the present invention to provide an apparatus and method for making better tasting beverages such as better tasting coffee, espresso, cappuccino, latte, or tea.
It is a further object of the present invention to provide an apparatus that has a more effective and powerful water and steam delivery system for uses in making beverages.
These and other objectives and advantages of the present invention will become apparent from the following description of the preferred embodiments, taken together with the accompanying drawings.